This invention relates generally to a seal for coaxial cable connectors, and more specifically, to an external seal for protecting the coaxial cable connector from exposure to environmental elements.
Telecommunication systems have evolved and flourished to provide many telecommunication services, such as cellular and wireless services, and cable television services. Cable television services include, but are not limited to digital television programming, voice over internet protocol (VoIP) services, broadband internet access, and pay-per-view ordering/billing/monitoring. Cellular and wireless services include, but are not limited to services like voice calling, short messaging service, multimedia messaging service, and internet access.
Coaxial cable is used extensively in telecommunication systems to transmit telecommunication signals. In some cases, such as with cable television services, telecommunication signals are delivered to residential or commercial premises by feeder cables running from a head end. Normally, the head end is a facility that houses electronic equipment used to receive and re-transmit video and other signals over a local cable infrastructure. The signals are usually received via satellite, and then redistributed along the feeder cables. The feeder cables extend from the head end and branch off to individual user's facilities along drop cables. These drop cables can be further divided to distribute signals along distribution cables on a user's facility to multiple end devices, such as televisions or modems. Signals are also returned or sent from user facilities in the telecommunication system along the same, but reverse path.
As can be envisioned from the above description, coaxial cable does not run as a single length from a head end to each and every end device. In routing the feeder cables, drop cables, and distribution cables to feed the signals to all the users in a local cable infrastructure, multiple lengths of cable are necessary. Multiple types of cable (e.g. feeder cable, drop cable, distribution cable) can be necessary; and multiple lengths of each type of cable can be necessary. Lengths of cable can be connected to each other by connecting to an intermediate device, such as an amplifier, splitter, or tap. A cable can connect to an end device, such as a television or modem. Often, a length of cable can or must be spliced. When spliced, two connectors join two lengths of the same type of cable, forming a consistent signal path with consistent signal qualities. The signals in coaxial cable are in the form of alternating electrical current, so coaxial cable connectors connecting two lengths of the same cable are designed and used to pass a consistent alternating electrical current without altering the electrical characteristics. Also possible in cable television systems, one length of one type or size of cable can be joined by a connector to another length of another type or size.
Coaxial cables are also used extensively in wireless systems, such as those providing cellular telephone services. In these systems, coaxial cables are used on cellular telephone towers. On each tower, coaxial cables run between antennas at the top and signal devices at the bottom. In these installations, often one length of one type or size of cable is joined by a connector to another length of another type or size. For instance, a large, hard line coaxial cable frequently carries high energy signals the length of a cellular tower. At each end, this hard line coaxial cable connects to a smaller, flexible coaxial cable that can connect to an antenna, or run to a signal device. In this case, the hard, inflexible coaxial cable is necessary to reduce signal loss of the high energy signals, while a smaller, short-length flexible coaxial cable is necessary to run the signal in various directions for convenience of routing.
In order to accommodate the various combinations of connections, including connections between the variously sized cables with various electrical characteristics, a large variety of coaxial cable connectors exist. The diversity of coaxial cable connectors is further increased by innovation over the years attempting to improve signal quality or meet other demands in the telecommunications industry, such as the need for weatherproof connections and connections shielded from undesirable RF noise.
In addition to the variety of coaxial cable connectors, the abundance of their use continues to grow as the telecommunication systems continue to develop and grow. A large percentage of these coaxial cable connectors are used outside, while another percentage of them are used inside a residential, commercial, or industrial property. Many are located underground, connecting underground cables, while some are exposed to the air.
With a growing variety and abundance of coaxial cable connector in use, damage to coaxial cable connectors becomes a potentially growing problem and cost. Damage can occur to cable connectors both indoors and outdoors, as the cable connectors are exposed to environmental hazards and weathering elements, particularly invading exterior matter. In particular, especially with cable connectors used outdoors, water invading the connector poses a significant threat of damage. Some forms of water include, but are not limited to, rain, condensation, mist, high relative humidity, and flooding. Even indoors, connectors are exposed to water, especially in basements, where they are frequently used. Especially dangerous is water in gaseous form, such as humidity or vapor, which can pervade air space around cable connectors and easily permeate very small openings.
When water gets inside a connector, it can cause significant damage. In particular, water can catalyze corrosion. Corroded parts can negatively affect the electrical characteristics of the cable connector, which can negatively alter signals carried along conductors therein. Water itself, even without corrosion, can negatively affect the electrical characteristics too. A short to ground from the conductor might occur, thereby stopping the signal from reaching its destination altogether.
Damage to coaxial cable connectors can cause significant problems in delivering telecommunication services. These problems can be financially costly as well. Any malfunction or degradation of the connector requires maintenance, as even minor signal alteration can cause major problems. Signal alteration, or loss of desirable signals can cause some form of disruption in the telecommunication services provided to a user. For instance, television images can be distorted, broken, or choppy, while internet can be slowed or lost. Jitter and delay problems with VoIP services can be further aggravated. VoIP services non-sequentially transmit audio as data packets. A delay exists in the transmission of the data packets, and jitter is a variation in delay receiving the data packets that can be caused by physical distance, congestion in the system, etc. Faulty connectors can promote delay or loss of some of these data packets which can disrupt the service or cause poor audio quality.
Furthermore, minor losses in signals returning or sent from user facilities can build up in telecommunication systems to reduce overall signal to noise ratios.
To prevent this buildup of signal loss, connectors must be maintained and/or repaired. Maintenance is costly. Diagnosing the problem can be difficult and time consuming. Once identified as a connector issue, connectors must be accessed and repaired, often by digging to expose them, or by accessing them on or in a user's facility. Prolonging the life of connectors by avoiding water damage or damage from other environmental dangers can save time and money, and preserve quality telecommunication services. However, damage is sometimes inevitable, and promoting access to connectors for easier repairing will also help save time and money.
In preventing damage to coaxial cable connectors, particular points of vulnerability that exist on coaxial cable connectors can be protected. These points, such as at joints or unions of two components comprising a single connector, or the union between two different connectors, can be particularly vulnerable to intrusion of external material, such as water, dirt, or other particulate matter. One current attempt to protect connectors includes the use of O-rings at these vulnerable points. O-rings are generally made of some form of plastic or rubber, so they can be compressed between two surfaces to form a seal. When an O-ring is used, it is positioned to establish the seal between two joined parts of a connector, or between two joined connectors. Another solution uses a sleeve positioned over the joint between the two connectors after the connectors are connected.
These solutions have shortcomings. In either case, the seal only protects a limited portion of the connector—mainly a single point of particular vulnerability. Furthermore, during installation of the seal and/or the connector, the seal might be installed incorrectly. Internal seals can be broken or damaged during installation, rendering them ineffective. Separately installed seals, such as seals installed in the field during installation of the connector in a cable television system, can be difficult to install and might be installed imperfectly. The imperfect installation might also result in seal damage.
Also, while there are often particular points of vulnerability, damage to the connector can occur at or from any external point on the connector or at a connection between multiple connectors, where current seals aimed to protect a specific location do not protect. Sometimes it is equally important to protect the entire connector rather than one or more single points. A long sleeve or heat-shrink wrapping can be accommodated to cover various lengths of a connector, or the connection between multiple connectors.
Again however, the use of heat-shrink tubing or a sleeve encounters disadvantages. Once installed, for instance, heat-shrink tubing is not removable and replaceable. A sleeve, too, though less permanent than heat-shrink tubing, would also be difficult to remove and replace. These solutions limit the ability to access coaxial cable connectors to perform maintenance, repair, or other functions requiring access. Additionally, the installation can be difficult or time-consuming, and installers might forget to, or choose not to, install them. Particularly during maintenance, if the seal is removed, and it is not easily reinstalled, the chances are greater the installer will choose not to reinstall it, or will reinstall it incorrectly. The seal might also be damaged in handling.
It would be advantageous to externally seal coaxial cable connectors from exposure to harmful elements without limiting access to the connectors, without leaving vulnerable portions exposed, and without adding disincentive to install the seals.